﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace ProcessMemoryReaderLib
{
    /// <summary>
    /// ProcessMemoryReader is a class that enables direct reading a process memory
    /// </summary>
    class ProcessMemoryReaderApi
    {
        // constants information can be found in <winnt.h>
        [Flags]
        public enum ProcessAccessType
        {
            PROCESS_TERMINATE = (0x0001),
            PROCESS_CREATE_THREAD = (0x0002),
            PROCESS_SET_SESSIONID = (0x0004),
            PROCESS_VM_OPERATION = (0x0008),
            PROCESS_VM_READ = (0x0010),
            PROCESS_VM_WRITE = (0x0020),
            PROCESS_DUP_HANDLE = (0x0040),
            PROCESS_CREATE_PROCESS = (0x0080),
            PROCESS_SET_QUOTA = (0x0100),
            PROCESS_SET_INFORMATION = (0x0200),
            PROCESS_QUERY_INFORMATION = (0x0400)
        }

        // function declarations are found in the MSDN and in <winbase.h> 

        //        HANDLE OpenProcess(
        //            DWORD dwDesiredAccess,  // access flag
        //            BOOL bInheritHandle,    // handle inheritance option
        //            DWORD dwProcessId       // process identifier
        //            );
        [DllImport("kernel32.dll")]
        public static extern IntPtr OpenProcess(UInt32 dwDesiredAccess, Int32 bInheritHandle, UInt32 dwProcessId);

        //        BOOL CloseHandle(
        //            HANDLE hObject   // handle to object
        //            );
        [DllImport("kernel32.dll")]
        public static extern Int32 CloseHandle(IntPtr hObject);

        //        BOOL ReadProcessMemory(
        //            HANDLE hProcess,              // handle to the process
        //            LPCVOID lpBaseAddress,        // base of memory area
        //            LPVOID lpBuffer,              // data buffer
        //            SIZE_T nSize,                 // number of bytes to read
        //            SIZE_T * lpNumberOfBytesRead  // number of bytes read
        //            );
        [DllImport("kernel32.dll")]
        public static extern Int32 ReadProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, [In, Out] byte[] buffer, UInt32 size, out IntPtr lpNumberOfBytesRead);

        //        BOOL WriteProcessMemory(
        //            HANDLE hProcess,                // handle to process
        //            LPVOID lpBaseAddress,           // base of memory area
        //            LPCVOID lpBuffer,               // data buffer
        //            SIZE_T nSize,                   // count of bytes to write
        //            SIZE_T * lpNumberOfBytesWritten // count of bytes written
        //            );
        [DllImport("kernel32.dll")]
        public static extern Int32 WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, [In, Out] byte[] buffer, UInt32 size, out IntPtr lpNumberOfBytesWritten);

    }

    public class ProcessMemoryReader
    {

        public ProcessMemoryReader()
        {
        }

        /// <summary>    
        /// Process from which to read        
        /// </summary>
        public Process ReadProcess
        {
            get
            {
                return m_ReadProcess;
            }
            set
            {
                m_ReadProcess = value;
            }
        }

        private Process m_ReadProcess = null;

        private IntPtr m_hProcess = IntPtr.Zero;

        public void OpenProcess()
        {
            //            m_hProcess = ProcessMemoryReaderApi.OpenProcess(ProcessMemoryReaderApi.PROCESS_VM_READ, 1, (uint)m_ReadProcess.Id);
            ProcessMemoryReaderApi.ProcessAccessType access;
            access = ProcessMemoryReaderApi.ProcessAccessType.PROCESS_VM_READ
                | ProcessMemoryReaderApi.ProcessAccessType.PROCESS_VM_WRITE
                | ProcessMemoryReaderApi.ProcessAccessType.PROCESS_VM_OPERATION;
            m_hProcess = ProcessMemoryReaderApi.OpenProcess((uint)access, 1, (uint)m_ReadProcess.Id);
        }

        public void CloseHandle()
        {
            int iRetValue;
            iRetValue = ProcessMemoryReaderApi.CloseHandle(m_hProcess);
            if (iRetValue == 0)
                throw new Exception("CloseHandle failed");
        }

        public byte[] ReadProcessMemory(IntPtr MemoryAddress, uint bytesToRead, out int bytesRead)
        {
            byte[] buffer = new byte[bytesToRead];

            IntPtr ptrBytesRead;
            ProcessMemoryReaderApi.ReadProcessMemory(m_hProcess, MemoryAddress, buffer, bytesToRead, out ptrBytesRead);

            bytesRead = ptrBytesRead.ToInt32();

            return buffer;
        }

        public void WriteProcessMemory(IntPtr MemoryAddress, byte[] bytesToWrite, out int bytesWritten)
        {
            IntPtr ptrBytesWritten;
            ProcessMemoryReaderApi.WriteProcessMemory(m_hProcess, MemoryAddress, bytesToWrite, (uint)bytesToWrite.Length, out ptrBytesWritten);

            bytesWritten = ptrBytesWritten.ToInt32();
        }




    }
}  
